Most interview prep hands you a list of problems and hopes the patterns sink in. This course teaches them first. Short written lessons take you from how to approach a problem you have never seen, through the core data structures, to the algorithm patterns coding interviews keep returning to, and every lesson ends in puzzles that use exactly what you just read.
The first lesson is not about any data structure. It is about the first five minutes of a problem you have never seen: recognize the pattern, build the brute force first, work a tiny case by hand, and name what makes it slow. That habit is what the rest of the course hangs on.
Arrays, strings, hash maps and sets, stacks, queues, linked lists, trees, heaps and priority queues, graphs and grids. Each lesson covers what the structure is good at, what its operations cost, and the kind of interview question that should make you reach for it.
Big-O, two pointers, sliding window, binary search, recursion, backtracking, BFS and DFS, sorting, greedy, bit manipulation and dynamic programming. These are the recurring shapes behind most coding interview questions, taught in an order where each one builds on the last.
A second track goes below the code, from first principles, in the order university systems courses teach it: bits and bytes, two's complement and floating point, big endian vs little endian, how RAM works, CPU caches and locality, pointers and struct padding, stack vs heap memory, virtual memory and paging, garbage collection, and finally space complexity counted from the machine up. It is the material behind half the questions a systems interview asks, and every lesson cites the lectures and papers it draws on.
Reading about a pattern is not the same as using it. Each lesson points at puzzles that use it, opened at the fill-in-the-blanks level so the key lines are taken out and you put them back. Every line of every solution has a note explaining why it is there, in whichever language you solve in. When the blanks feel easy, the same puzzle goes up to typing it from scratch, and from there to a mock interview on it.
Finish a path and you get a certificate with a verification link. The link opens a page that confirms the certificate is real, so it can go on a resume or a profile and be checked by whoever reads it, rather than being a picture of a badge.
31 lessons, about 6 hours of reading in all.
The opening section of every lesson is free to read with no account. Premium unlocks the rest of each lesson and the practice puzzles it points at.
You need to be able to read basic code in Python, JavaScript or C++. The lessons explain the ideas in plain English, and every practice puzzle can be solved in any of the three.
Yes. The Computer Memory module starts from a single bit and works up to a running program: two's complement, endianness, caches, the stack and the heap, virtual memory and garbage collection, and ends on space complexity. Each lesson ends in puzzles that make you implement the idea, such as simulating a cache or finding a stack overflow.
It covers the patterns most coding interviews are built from, which is the part you can study. The rest is practice under pressure, which is what the puzzle library and the AI mock interview are for. A sensible order is a lesson, its puzzles, then the same puzzles typed from scratch, then an interview.
Then practice the interview itself, or browse all 576 practice puzzles.